Minimally invasive surgical (MIS) instruments are often preferred over traditional open surgical devices due to reduced post-operative recovery time and minimal scarring. Endoscopic surgery is one type of MIS procedure in which an elongate flexible shaft is introduced into the body of a patient through a natural orifice. Laparoscopic surgery is another type of MIS procedure in which one or more small incisions are formed in the abdomen of a patient and a trocar is inserted through the incision to form a pathway that provides access to the abdominal cavity. Through the trocar, a variety of instruments and surgical tools can be introduced into the abdominal cavity, and the trocar also helps facilitate insufflation to elevate the abdominal wall above the organs. The instruments and tools introduced into the abdominal cavity via the trocar can be used to engage and/or treat tissue in a number of ways to achieve a diagnostic or therapeutic effect.
Various robotic systems have recently been developed to assist in MIS procedures. Robotic systems can allow for more intuitive hand movements by maintaining natural eye-hand axis. Robotic systems can also allow for more degrees of freedom in movement by including a “wrist” joint on the instrument, which creates a more natural hand-like articulation.
To facilitate the wrist joint, robotic systems typically include a cable driven motion system designed to articulate (move) an end effector of a surgical instrument. Cable driven motion systems typically include one or more drive cables that extend between a drive housing and the end effector. The drive housing is mounted to and otherwise attached to a robotic manipulator that has a plurality of input drives operatively coupled to the drive cables. During operation, the input drives are selectively actuated to move the drive cables and thereby articulate the end effector in a desired manner.
Through operation of the input drives, the drive cables typically assume large tensile loads, which must be released or eased prior to detaching the drive housing from the robotic manipulator. If such tensile loads are not previously released, detaching the drive housing from the robotic manipulator can suddenly release the tension in the drive cables, which, in extreme cases, could launch the drive housing from the robotic manipulator and potentially damage the drive housing or harm a user. What is needed is a manual method, independent of the robotically controlled systems to manage cable tension, to provide a safe alternative to disconnecting the drive housing from the robotic manipulator by a user (e.g., surgeon, clinician, etc.) during emergency conditions or when the robotic system is not functioning properly.